Medium conveying apparatus

ABSTRACT

A medium conveying apparatus includes a medium tray on which a medium is placed, a skew corrector that rotates the medium in such a manner that a part of an end of the medium is aligned with a predetermined line, a rotating member that contacts with the medium, and a conveyor that conveys the medium in a conveying direction, wherein the rotating member is supported rotatably on the medium tray so that, when the medium moves in a direction different from the conveying direction, the rotating member rotates following the medium.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Application No. PCT/JP2019/011923, filed on Mar. 20, 2019, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are related to a medium conveying apparatus.

BACKGROUND

A medium conveying apparatus for correcting a skew has been known that, when a medium that is conveyed is skewed, corrects a skew so that the medium is less tilted (see Japanese Laid-open Patent Publication No. H10-250877). Such a medium conveying apparatus alleviates cumbersomeness of aligning media for a user, and prevents paper jamming of a medium, caused by a skew.

However, sometimes such a skew of a medium placed on a medium tray is not corrected appropriately due to the friction between the medium and the medium tray.

SUMMARY

According to an aspect of an embodiment, a medium conveying apparatus includes a medium tray on which a medium is placed, a skew corrector that rotates the medium in such a manner that a part of an end of the medium is aligned with a predetermined line, a rotating member that contacts with the medium, and a conveyor that conveys the medium in a conveying direction, wherein the rotating member is supported rotatably on the medium tray so that, when the medium moves in a direction different from the conveying direction, the rotating member rotates following the medium.

The object and advantages of the disclosure will be realized and attained by means of the elements and combinations particularly pointed out in the claims.

It is to be od that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side sectional view illustrating an image reading apparatus provided with a medium conveying apparatus according to the first embodiment;

FIG. 2 is a perspective view illustrating the image reading apparatus;

FIG. 3 is a sectional view illustrating a rotating ball;

FIG. 4 is a side view illustrating a separator;

FIG. 5 is a perspective view illustrating a medium tray and a skew corrector;

FIG. 6 is a plan view illustrating media that are conveyed by the separator;

FIG. 7 is a perspective view illustrating a medium tray of a medium conveying apparatus according to a second embodiment;

FIG. 8 is a perspective view illustrating a medium tray of a medium conveying apparatus according to a third embodiment;

FIG. 9 is a perspective view illustrating a medium conveying apparatus according to a fourth embodiment;

FIG. 10 is a side view illustrating a separator of a medium conveying apparatus according to a fifth embodiment; and

FIG. 11 is a plan view illustrating a medium that is conveyed by a separator of the medium conveying apparatus according to the fifth embodiment.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the disclosure will be explained with reference to accompanying drawings. A medium conveying apparatus according to some embodiments of the present disclosure will be explained with reference to some drawings. The following description is, however, not intended to limit the scope of the technology according to the present disclosure in any way. Furthermore, in the following description, the same elements are given the same reference numerals, and redundant explanations thereof will be omitted.

First Embodiment

A medium conveying apparatus according to a first embodiment is provided to an image reading apparatus 1, as illustrated in FIG. 1. FIG. 1 is a side sectional view illustrating the image reading apparatus 1 provided with the medium conveying apparatus according to the first embodiment. The image reading apparatus 1 includes an image reading apparatus main body 2 and a medium tray 3. The image reading apparatus main body 2 has a box-like shape, and placed on an installation surface 5 where the image reading apparatus 1 is installed. The image reading apparatus main body 2 has a sheet feed opening 6 and a discharge opening 7. The sheet feed opening 6 is formed on the rear side of the image reading apparatus 1. The discharge opening 7 is formed on the front side of the image reading apparatus 1 where the sheet feed opening 6 is formed.

The medium tray 3 is disposed near the sheet feed opening 6 on the rear side of the image reading apparatus main body 2. The medium tray 3 has a placing surface 8. The medium tray 3 is positioned in an inclined manner such that the distance between an end of the placing surface 8 that is on a side closer to the sheet feed opening 6 and the installation surface 5 is smaller than the distance between another end of the placing surface 8 that is on a side farther from the sheet feed opening 6 and the installation surface 5, and is fixed to the image reading apparatus main body 2.

The image reading apparatus main body 2 further has a conveying path 14. The conveying path 14 is formed inside the image reading apparatus main body 2. One end of the conveying path 14 is connected to the sheet feed opening 6, and the other end of the conveying path 14 is connected to the discharge opening 7.

The image reading apparatus 1 further includes a conveyor 20. The conveyor 20 includes a skew corrector 21, a feed roller 22, and a pressure roller 23. The skew corrector 21 includes a separator 24 and registration roller pairs 25. The separator 24 is disposed near the sheet feed opening 6 of the conveying path 14. The registration roller pairs 25 are disposed between the separator 24 and the discharge opening 7 in the conveying path 14.

The feed roller 22 has a cylindrical shape. The feed roller 22 is disposed between the lower registration roller pair 25 and the discharge opening 7 in the conveying path 14, and is supported rotatably on the image reading apparatus main body 2. The pressure roller 23 has a cylindrical shape. The pressure roller 23 is disposed above the conveying path 14 and on top of the upper feed roller 22. The pressure roller 23 is supported rotatably on the image reading apparatus main body 2. The pressure roller 23 presses a medium disposed in the conveying path 14 against the feed roller 22. By rotating counterclockwise in FIG. 1, the feed roller 22 conveys the medium that is pressed against the feed roller 22 toward the discharge opening 7, along the conveying path 14.

The image reading apparatus 1 includes a lower side reader 26 and an upper side reader 27. The lower side reader 26 is implemented as a contact image sensor (CIS). The lower side reader 26 is disposed below the conveying path 14, and between the registration roller pair 25 and the feed roller 22. The lower side reader 26 reads the image on the bottom surface of the medium that is conveyed along the conveying path 14. The upper side reader 27 is implemented as a CIS. The upper side reader 27 is disposed above the conveying path 14, on top of the lower side reader 26, and between the upper registration roller pair 25 and the pressure roller 23. The upper side reader 27 reads the image on the top surface of the medium conveyed along the conveying path 14.

FIG. 2 is a perspective view illustrating the image reading apparatus 1. The image reading apparatus 1 further includes a rotating ball 31. The rotating ball 31 is disposed substantially at the center of the medium tray 3. The rotating ball 31 has a spherical shape, as illustrated in FIG. 3. FIG. 3 is a sectional view illustrating the rotating ball 31. The rotating ball 31 is disposed in such a manner that a part of the rotating ball 31 projects out from the placing surface 8 of the medium tray 3, and that the remaining part of the rotating ball 31 is embedded in the medium tray 3. The rotating ball 31 is supported rotatably in 360-degree directions about a center point 32 of the ball on the medium tray 3.

The part of the rotating ball 31 projecting out from the placing surface 8 has a medium contact portion 33, and a segment 35 connecting the medium contact portion 33 and the center point is perpendicular to a plane 34. The medium contact portion 33 is contacts with a medium 36 placed on the medium tray 3.

FIG. 4 is a side view illustrating the separator 24. The separator 24 includes a separating roller 41 and a brake roller 42. The separating roller 41 has a cylindrical shape, and is disposed below the conveying path 14. The separating roller 41 is supported rotatably on the image reading apparatus main body 2. The brake roller 42 is disposed above the conveying path 14 and on top of the separating roller 41 such that the brake roller 42 contacts with the separating roller 41. The brake roller 42 is supported rotatably on the image reading apparatus main body 2.

The separator 24 includes a driving source and a toque limiter that are not illustrated. The driving source generates a rotating force. The separating roller 41 is rotated forwardly counterclockwise in FIG. 4, by receiving the rotating force generated by the driving source. The toque limiter transmits the rotating force generated by the driving source to the brake roller 42 when the load exerted on the brake roller 42 is less than a predetermined force, and does not transmit the rotating force generated by the driving source to the brake roller 42 when the load exerted on the brake roller 42 is greater than the predetermined force. By receiving the rotating force generated by the driving source, the brake roller 42 is rotated reversely counterclockwise in FIG. 4. Because the rotating force is transmitted to the brake roller 42 via the toque limiter, the brake roller 42 receives a load greater than the predetermined force when the brake roller 42 is brought into contact with the separating roller 41, and is rotated forwardly clockwise following the separating roller 41.

Because the medium tray 3 is inclined, a plurality of media 43 placed on the medium tray 3 move toward the separator 24 due to their own weight, and are brought into contact with the separating roller 41 and the brake roller 42. The separating roller 41 moves the media 43 to enter between the separating roller 41 and the brake roller 42 by rotating forwardly. When a plurality of media are nipped between the separating roller 41 and the brake roller 42, the brake roller 42 does not receive a load greater than the predetermined force, and is rotated reversely. The brake roller 42 conveys the media nipped between the separating roller 41 and the brake roller 42 and not in contact with the separating roller 41 toward the medium tray 3 by rotating reversely. The separating roller 41 conveys a medium 44 in contact with the separating roller 41 along the conveying path 14 in a conveying direction 45 by rotating forwardly. When one medium 44 is nipped between the separating roller 41 and the brake roller 42, the brake roller 42 receives a load greater than the predetermined force from the separating roller 41 via the medium 44, and is rotated forwardly by following the separating roller 41.

FIG. 5 is a perspective view illustrating the medium tray 3 and the skew corrector 21. The registration roller pairs 25 include a right feed roller 51, a left feed roller 52, a right pressure roller 53, and a left pressure roller 54. The right feed roller 51 has a cylindrical shape, is disposed below the conveying path 14, and is supported rotatably about a rotational axis 55 on the image reading apparatus main body 2. The rotational axis 55 is in parallel with the plane along the placing surface 8, and perpendicular to the conveying direction 45. The left feed roller 52 has a cylindrical shape with the same radius as that of the right feed roller 51. The left feed roller 52 is disposed below the conveying path 14, and is supported rotatably about the rotational axis 55 on the image reading apparatus main body 2.

The right pressure roller 53 has a cylindrical shape, is disposed above the conveying path 14 such that the right pressure roller 53 contacts with the right feed roller 51, and is supported rotatably about a rotational axis 56 on the image reading apparatus main body 2. The rotational axis 56 is in parallel with the rotational axis 55. The left pressure roller 54 has a cylindrical shape with the same radius as that of the right pressure roller 53. The left pressure roller 54 is disposed above the conveying path 14 such that the left pressure roller 54 contacts with the left feed roller 52, and is supported rotatably about the rotational axis 56 on the image reading apparatus main body 2.

Operation of Image Reading Apparatus 1

When a user wants to read the image on one medium using the image reading apparatus 1, the user places the one medium on the medium tray 3, and when the user wants to read the images on a plurality of respective media using the image reading apparatus 1, the user places the media on the medium tray 3. Because the medium tray 3 is inclined, the medium placed on the medium tray 3 moves toward the sheet feed opening 6 along the placing surface 8 in the conveying direction 45 due to its own weight, is inserted into the sheet feed opening 6, and is brought into contact with the separator 24. At this time, the rotating ball 31 is rotated following the medium, so that the medium contact portion 33 moves in the conveying direction 45. Because the rotating ball 31 rotates following the medium, the frictional force that prevents the medium from moving along the medium tray 3 is reduced, so that the image reading apparatus 1 can move the medium reliably, and bring the medium into contact with the separator 24, appropriately.

After placing the medium on the medium tray 3, a user starts an image reading operation of the image reading apparatus 1, by operating the image reading apparatus 1. Once the image reading operation is started, the separator 24 rotates the separating roller 41 forwardly, and rotates the brake roller 42 reversely, while keeping the registration roller pairs 25 not rotated. The separating roller 41 moves the medium in contact with the separator 24 to enter between the separating roller 41 and the brake roller by rotating forwardly, and the medium is nipped between the separating roller 41 and the brake roller 42. The brake roller 42 conveys the media nipped between the separating roller 41 and the brake roller 42 and not in contact with the separating roller 41 toward the medium tray 3 by rotating reversely.

The separating roller conveys the one medium in contact with the separating roller 41 along the conveying path 14 toward the registration roller pairs 25 in the conveying direction 45 by rotating forwardly. When one medium is nipped between the separating roller 41 and the brake roller 42, the brake roller 42 receives a load greater than the predetermined force from the separating roller 41 via the medium 44, and is rotated forwardly by following the separating roller 41.

When a plurality of media 62 placed on the medium tray 3 are not aligned with one another, sometimes one medium 61 that is conveyed by the separator 24 is skewed, as illustrated in FIG. 6. FIG. 6 is a plan view illustrating the medium 61 that is conveyed by the separator 24. In other words, sometimes a leading end 63 of the medium 61 abuts against the left feed roller 52 of the skew corrector 21 before abutting against the right feed roller 51. After the leading end 63 abuts against the left feed roller 52, the medium 61 is rotated by being further conveyed by the separator 24 so that the leading end 63 moves closer to the right feed roller 51. As a result of the medium 61 being rotated, the leading end 63 abuts against both of the left feed roller 52 and the right feed roller 51. When the leading end 63 abuts against both of the left feed roller 52 and the right feed roller 51, the medium 61 has its skew corrected, and has been positioned such that the line extending along the leading end 63 is in parallel with the rotational axis 55.

Sometimes the leading end 63 of the medium 61 abuts against the right feed roller 51 of the skew corrector 21 before abutting against the left feed roller 52. After the leading end 63 abuts against the right feed roller 51, the medium 61 is rotated by being further conveyed by the separator 24 so that the leading end 63 moves closer to the left feed roller 52. As a result of the medium 61 being rotated, the leading end 63 abuts against both of the left feed roller 52 and the right feed roller 51. When the leading end 63 abuts against both of the left feed roller 52 and the right feed roller 51, the medium 61 has its skew corrected, and has been positioned such that the line extending along the leading end 63 is in parallel with the rotational axis 55.

When the medium is rotated, the rotating ball 31 is further rotated following the medium so that the medium contact portion 33 moves in a direction different from the conveying direction 45. Because the rotating ball 31 rotates following the medium, the frictional force that prevents the medium from rotating with respect the medium tray 3 is reduced, so that the image reading apparatus 1 can rotate the medium appropriately, and can correct the skew of the medium appropriately.

The separating roller 41 is started being rotated forwardly, and after a lapse of a predetermined time, the skew corrector 21 allows the right feed roller 51 and the left feed roller 52 to rotate forwardly. The predetermined time is set to a time period sufficient for the leading end 63 of the medium 61 to abut against both of the left feed roller 52 and the right feed roller 51 after the separating roller 41 is rotated forwardly. The right feed roller 51 moves a part of the medium abutting the right feed roller 51 to enter between the right feed roller 51 and the right pressure roller 53 by rotating forwardly, and the part is pressed against the right feed roller 51 by the right pressure roller 53. The left feed roller 52 moves a part of the medium abutting the left feed roller 52 to enter between the left feed roller 52 and the left pressure roller 54 by rotating forwardly, and the part is pressed against the left feed roller 52 by the left pressure roller 54. The right feed roller 51 and the left feed roller 52 convey, by rotating forwardly, the medium that is pressed against the right feed roller 51 and the left feed roller 52 toward the discharge opening 7 along the conveying path 14 in a state where the skew is corrected.

The medium that is conveyed along the conveying path 14 toward the discharge opening 7 by the right feed roller 51 and the left feed roller 52 is conveyed between the lower side reader 26 and the upper side reader 27 of the conveying path 14. The lower side reader 26 then captures an image of the bottom surface of the medium that is conveyed along the conveying path 14. The upper side reader 27 captures an image of the top surface of the medium that is conveyed along the conveying path 14.

When the right feed roller 51 and the left feed roller 52 are rotating forwardly, the conveyor 20 rotates the feed roller 22 forwardly. The medium having been conveyed between the lower side reader 26 and the upper side reader 27 then contacts with the feed roller 22 and the pressure roller 23. The feed roller 22 moves the medium having been contacted with the feed roller 22 and the pressure roller 23 to enter between the feed roller 22 and the pressure roller 23 by rotating forwardly, and the medium is pressed against the feed roller 22 by the pressure roller 23. The feed roller 22 conveys the medium pressed against the feed roller 22 toward the discharge opening 7 along the conveying path 14 and discharges the medium from the discharge opening 7 by rotating forwardly.

Effects Achieved by Medium Conveying Apparatus According to First Embodiment

The medium conveying apparatus according to the first embodiment includes the medium tray 3 on which a medium is placed; the skew corrector 21 that rotates the medium in such a manner that the leading end of the medium is aligned with a predetermined line; the rotating ball 31 that contacts with the medium; and the conveyor 20 that conveys the medium in the conveying direction 45. The rotating ball 31 is supported rotatably on the medium tray 3 so that, when the medium moves in a direction different from the conveying direction 45, the rotating ball 31 rotates following the medium. Because the rotating ball rotates following the medium when the skew corrector 21 corrects the skew of the medium, the frictional force that prevents the medium from rotating with respect to the medium tray 3 is reduced, so that the medium conveying apparatus can correct the skew of the medium appropriately.

The medium conveying apparatus according to the first embodiment further includes the separator 24 that separates a medium that is in contact with the medium tray 3, from a plurality of media placed on the medium tray 3. The frictional force exerted on the bottommost medium of the media placed on the medium tray 3 is greater than the frictional force exerted on the topmost medium of the media placed on the medium tray 3. Even when the medium conveying apparatus is a bottom feed apparatus in which the bottommost medium is separated from the media placed on the medium tray 3, the medium conveying apparatus can correct the skew of the medium appropriately by reducing the frictional force that prevents the medium from rotating with respect to the medium tray 3.

Furthermore, because the rotating ball 31 of the medium conveying apparatus according to the first embodiment is rotatable in the 360-degree directions, the rotating ball 31 is also rotatable in the conveying direction 45. Because the rotating ball 31 rotates in the conveying direction 45, the frictional force exerted on the medium as the medium is conveyed is reduced, so that the medium conveying apparatus according to the first embodiment can convey the medium appropriately.

Second Embodiment

The medium conveying apparatus according to the first embodiment described above is provided with one rotating ball 31, but may be provided with a plurality of rotating balls. A medium conveying apparatus according to a second embodiment is the same as the medium conveying apparatus according to the first embodiment described above, except that it further includes another rotating ball 71, and the other parts are the same as those in the medium conveying apparatus according to the first embodiment described above, as illustrated in FIG. 7. FIG. 7 is a perspective view illustrating the medium tray 3 in the medium conveying apparatus according to the second embodiment. The rotating ball 71 has the same spherical shape as the rotating ball 31, and is disposed on the side nearer to the sheet feed opening 6 than the rotating ball 31 on the medium tray 3, and is supported rotatably in the 360-degree directions about the center point of the ball on the medium tray 3.

Because the rotating ball 71 rotates following the medium when the medium is rotated with respect to the medium tray 3 in the same manner as the rotating ball 31, the frictional force exerted on the medium by the medium tray 3 can be reduced. Hence, compared with the medium conveying apparatus according to the first embodiment described above, the medium conveying apparatus according to the second embodiment can reduce the frictional force exerted on the medium by the medium tray 3 more, and correct the skew of the medium more appropriately.

Third Embodiment

A medium conveying apparatus according to a third embodiment is the same as the medium conveying apparatus according to the second embodiment described above, except that it further includes a right rotating ball 72 and a left rotating ball 73, and the other parts are the same as those in the medium conveying apparatus according to the second embodiment described above, as illustrated in FIG. 8. FIG. 8 is a perspective view illustrating the medium tray 3 of the medium conveying apparatus according to the third embodiment. The right rotating ball 72 has a spherical shape, in the same manner as the rotating ball 31, is disposed on the right side of the rotating ball 31 and the rotating ball 71 on the medium tray 3, and is supported rotatably in the 360-degree directions about the center point of the ball on the medium tray 3. The left rotating ball 73 has a spherical shape, in the same manner as the rotating ball 31, is disposed on the left side of the rotating ball 31 and the rotating ball 71 on the medium tray 3, and is supported rotatably in the 360-degree directions about the center point of the ball on the medium tray 3. The right rotating ball 72 and the left rotating ball 73 are disposed symmetrically with respect a line crossing the rotating ball 31 and the rotating ball 71.

Because when the medium is rotated with respect to the medium tray 3, the right rotating ball 72 and the left rotating ball 73 rotate following the medium in the same manner as the rotating ball 31, the right rotating ball 72 and the left rotating ball 73 can reduce the frictional force exerted on the medium by the medium tray 3. Hence, compared with the medium conveying apparatus according to the second embodiment described above, the medium conveying apparatus according to the third embodiment can reduce the frictional force exerted on the medium by the medium tray 3 more, and correct the skew of the medium more appropriately.

Fourth Embodiment

The rotating ball 31 in the medium conveying apparatus according to the first embodiment described above is supported rotatably in the 360-degree directions about the center point of the ball on the medium tray 3, but may be supported rotatably about one rotational axis on the medium tray 3. In a medium conveying apparatus according to a fourth embodiment, as illustrated in FIG. 9, the rotating ball 31 in the medium conveying apparatus according to the first embodiment described above is replaced with a right rotating member 81, a left rotating member 82, and a central rotating member 83, but the other parts are the same as those in the medium conveying apparatus according to the first embodiment described above. FIG. 9 is a perspective view illustrating the medium conveying apparatus according to the fourth embodiment. The right rotating member 81 has a cylindrical shape, is disposed on the side nearer to the right side face of the medium tray 3, and is supported rotatably about a rotational axis 84 on the medium tray 3. The rotational axis 84 extends in parallel with the plane along the placing surface 8, and is inclined with respect to the conveying direction 45 so as not to be perpendicular to the conveying direction 45, nor in parallel with the conveying direction 45. The left rotating member 82 has a cylindrical shape, is disposed on the side nearer to the left side face of the medium tray 3, and is supported rotatably about a rotational axis 85 on the medium tray 3. The rotational axis 85 extends in parallel with the plane along the placing surface 8, and is inclined with respect to the conveying direction 45 so as not to be perpendicular to the conveying direction 45, nor in parallel with the conveying direction 45. The central rotating member 83 has a cylindrical shape, is disposed at the center between the right rotating member 81 and the left rotating member 82 on the medium tray 3, and is supported rotatably about a rotational axis 86 on the medium tray. The rotational axis 86 extends in parallel with the conveying direction 45.

Because when the skew of the medium is corrected by the skew corrector 21, the central rotating member 83 in contact with the medium placed on the medium tray 3 rotates following the medium about the rotational axis 86 in parallel with the conveying direction 45, the frictional force exerted on the medium by the medium tray 3 as the skew of the medium is corrected can be reduced, so that the skew of the medium can be corrected appropriately.

Furthermore, the right rotating member 81 and the left rotating member 82 are formed rotatably in directions that are substantially the same as those in which the medium placed on the medium tray 3 is rotated when the skew corrector 21 corrects the skew. Therefore, the right rotating member 81 and the left rotating member 82 can reduce the frictional force exerted on the medium by the medium tray 3 when the skew of the medium is corrected, so that the skew of the medium can be corrected appropriately. In other words, the medium conveying apparatus according to the fourth embodiment can reduce the frictional force exerted on the medium by the medium tray 3 when the skew of the medium is corrected in the same manner as the medium conveying apparatus according to the embodiments described above, and can correct the skew of the medium appropriately.

Fifth Embodiment

The separator 24 of the medium conveying apparatus according to the first embodiment described above separates the bottommost medium of the media placed on the medium tray 3, but the separator 24 may be configured to separate the topmost medium of the media placed on the medium tray 3. A medium conveying apparatus according to a fifth embodiment is the same as the medium conveying apparatus according to the first embodiment described above except that the separator 24 is replaced with another separator 91, as illustrated in FIG. 10, and the other parts are the same as those in the medium conveying apparatus according to the first embodiment described above. FIG. 10 is a side view illustrating the separator 91 of the medium conveying apparatus according to the fifth embodiment. The separator 91 includes a separating roller 92 and a brake roller 93. The separating roller 92 has a cylindrical shape, and is disposed above the conveying path 14. The separating roller 92 is supported rotatably on the image reading apparatus main body 2. The brake roller 93 is disposed below the conveying path 14 and under the separating roller 92 such that the brake roller 93 contacts with the separating roller 92. The brake roller 93 is supported rotatably on the image reading apparatus main body 2.

The separator 91 includes a driving source and a toque limiter that are not illustrated. The driving source generates a rotating force. The separating roller 92 is rotated forwardly clockwise in FIG. 10, by receiving the rotating force generated by the driving source. The toque limiter transmits the rotating force generated by the driving source to the brake roller 93 when the load exerted on the brake roller 93 is less than a predetermined force, and does not transmit the rotating force generated by the driving source when the load exerted on the brake roller 93 is greater than the predetermined force. By receiving the rotating force generated by the driving source, the brake roller 93 is rotated reversely clockwise in FIG. 10. Because the rotating force is transmitted to the brake roller 93 via the toque limiter, the brake roller 93 receives a load greater than the predetermined force when the brake roller 93 contacts with the separating roller 92, and rotates forwardly counterclockwise by following the separating roller 92.

Because the medium tray 3 is inclined, a plurality of media 94 placed on the medium tray 3 move toward the separator 91 due to their own weight, and contact with the separating roller 92 and the brake roller 93. The separating roller 92 moves the media 94 to enter between the separating roller 92 and the brake roller 93 by rotating forwardly. When a plurality of media are nipped between the separating roller 92 and the brake roller 93, the brake roller 93 does not receive a load greater than the predetermined force, and rotates reversely. The brake roller 93 conveys the media nipped between the separating roller 92 and the brake roller 93 and not in contact with the separating roller 92 toward the medium tray 3 by rotating reversely. The separating roller 92 conveys a medium 95 in contact with the separating roller 92 along the conveying path 14 in the conveying direction 45 by rotating forwardly. When one medium 95 is nipped between the separating roller 92 and the brake roller 93, the brake roller 93 receives a load greater than the predetermined force from the separating roller 92 via the medium 95, and rotates forwardly following the separating roller 92.

When a plurality of media 94 placed on the medium tray 3 are not aligned with one another, sometimes the medium 95 that is conveyed by the separator 91 is skewed, as illustrated in FIG. 11. FIG. 11 is a plan view illustrating the medium 95 that is conveyed by the separator 91 of the medium conveying apparatus according to the fifth embodiment. In other words, sometimes a leading end 96 of the medium 95 abuts against the left feed roller 52 before abutting against the right feed roller 51. After the leading end 96 of the medium 95 abuts against the left feed roller 52, the medium 95 is rotated by being further conveyed by the separator 91 so that the leading end 96 moves closer to the right feed roller 51. As a result of the medium 95 being rotated, the leading end 96 abuts against both of the left feed roller 52 and the right feed roller 51. When the leading end 96 abuts against both of the left feed roller 52 and the right feed roller 51, the medium 95 has its skew corrected, and has been positioned such that the line extending along the leading end 96 is in parallel with the rotational axis 55. Sometimes the leading end 96 of the medium 95 abuts against the right feed roller 51 before abutting against the left feed roller 52. In such a case, too, the medium 95 is rotated in such a manner that the medium 95 abuts against both of the left feed roller 52 and the right feed roller 51, and its skew is corrected.

When a frictional force between the media 94 and the medium 95 is large, the media 94 are rotated together with the medium 95 as a result of the medium 95 being rotated. When the media 94 are rotated with the medium 95, the rotating ball 31 rotates following the media 94. In the medium conveying apparatus according to the fifth embodiment, because the rotating ball 31 rotates following the media 94, the frictional force that prevents the media 94 from being rotated with respect to the medium tray 3 is reduced, so that the media 94 can be rotated appropriately. Because the media 94 are rotated appropriately, the medium conveying apparatus according to the fifth embodiment can correct the skew of the medium 95 appropriately.

The skew corrector 21 of the medium conveying apparatus according to the first embodiment described above corrects the skew of the medium using a configuration with registration rollers, but may also use any other configurations to correct the skew of the medium. Examples of such configurations include a configuration that uses an abutting member, and a configuration that uses an independent driving roller. The configuration using an abutting member has been publicly known, and is disclosed in Japanese Patent Application Laid-open No. 2000-136051. The configuration using independent driving rollers has also been publicly known, and is disclosed in Japanese Patent Application Laid-open No. 2000-95384. The medium conveying apparatus according to the embodiments described above can reduce the frictional force exerted on a medium when the medium is rotated, and correct the skew of the medium appropriately even when the skew of the medium is corrected using any another configuration.

Although the medium conveying apparatus according to the embodiments described above is used in an image reading apparatus, the medium conveying apparatus may also be used in another apparatus. An example of such an apparatus includes a printer. For example, when the medium conveying apparatus is used in a printer, the reader is replaced with a printing unit that prints a shape onto a medium. With the medium conveying apparatus according to the embodiments described above, the skew of the medium can be corrected appropriately even when the medium conveying apparatus is used in an apparatus that is different from the image reading apparatus.

The medium conveying apparatus disclosed herein can correct a skew of a medium appropriately.

All examples and conditional language recited herein are intended for pedagogical purposes of aiding the reader in understanding the disclosure and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the disclosure. Although the embodiments of the disclosure have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the disclosure. 

What is claimed is:
 1. A medium conveying apparatus comprising: a medium tray on which a medium is placed; a skew corrector that rotates the medium in such a manner that a part of an end of the medium is aligned with a predetermined line; a rotating member that is contacts with the medium; and a conveyor that conveys the medium in a conveying direction, wherein the rotating member is supported rotatably on the medium tray so that, when the medium moves in a direction different from the conveying direction, the rotating member rotates following the medium.
 2. The medium conveying apparatus according to claim 1, further comprising a separator that separates the medium that is in contact with the medium tray, out of a plurality of media placed on the medium tray.
 3. The medium conveying apparatus according to claim 1, wherein the rotating member is supported rotatably on the medium tray so as to further rotate in the conveying direction.
 4. The medium conveying apparatus according to claim 1, further comprising an other rotating member that contacts with the medium, wherein the other rotating member is supported rotatably on the medium tray so that, when the medium moves in a direction different from the conveying direction, the other rotating member is rotated following the medium. 